Intentional abuse of anabolic androgenic drugs (AASs) by athletes has been increased rapidly in many countries. Therefore, investigations are needed for studying the adverse effects of these drugs. Administration of three doses of Sustanon 250mg (3, 5 and 10mg/kg.B.wt) which includes four testosterone derivatives and taken by athletes as body builder androgenic drug has caused several biochemical, and histological alterations in the testes of rats. The biochemical changes included the increase of serum testosterone and malondialdehyde (MDA) levels while the histological effect included the degeneration of the germinal epithelium and the appearance of multinucleated giant cells and several variable sized vacuoles in a stage-like changes. The multinucleated giant cells appeared having a large number of apoptotic-like nuclei with marginated chromatin. This study has also showed a significant decrease of the epididymis sperm count. The later result has been confirmed by scanning electron micrographs. All these changes were observed in a dose related pattern.